mid drf-speed-hack
One more round of compressing histograms

They remain toooo large.  mnist sees >1.3gig histogram data at the peak.
merge w /master
enhanced comparison if inspect and summary min/max/mean/sigma
reduce to 1000 cols for now
Merge branch 'master' of github.com:0xdata/h2o
Added h2o.glmgrid
Added H2OGLMGridModel
Added __Page_GLMGrid